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dadrummond 18

I'm working making a 3D printed trilobite. I'm new to FF, lured here by so many informative posts and pictures, some of which have been invaluable in modeling this "bug." Here's a look at the 3D model so far, made and rendered in Blender. (My avatar provides another view.)

If anyone has pictures of specimens of this species group (which I hope the experts can easily identify!), particularly with soft tissues preserved, I would be very grateful for pointers. I've been working from the Harrington 1959 reconstruction, salted with specimens found here and elsewhere online, spiced with a little imagination, and served with a giant helping of 3D printing constraints. The biggest constraint is that the frilly details won't survive the 3D printing post-processing; secondarily, I want to make something robust enough for people to handle.

I'm doing this because I always wanted to hold a trilobite, to pick one up out of the rock, turn it over, run my fingers along the spines. Wandering the forums, I get the feeling that I'm not alone!

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dadrummond 18

Thanks ZC, yes, I've spent a lot of time staring at the amazing pyritized Triarthus specimens. I don't have a good sense of how similar the leg morphology is in Ceraurus, the genus I'm modeling. GerryK posted pictures here of a Ceraurus with soft-tissue preservation a year and a half ago, and I've pinged him to see if there are any updates. This is clearly the place to be.

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dadrummond 18

Today I have several 3D prints of this trilobite model, a model which I'm still changing in ways large and small. Here's one of the first prints I made, and in the next few posts I'll explain how I made it, from modeling to printing. This is 3D printed on a Formlabs Form 1 3D printer in clear resin.

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dadrummond 18

The first step in this project was to look at as many trilobites as possible and choose one. I've always loved these fossils, but the moment they turned from fossils into living organisms for me was when I saw the new generation of preparations displayed at Chicago's Field Museum. I couldn't believe what I was seeing. In my mind, trilobites were flat, if beautiful, primitive creatures. Seeing those preparations made it clear how not-flat and not-primitive they were. I'd previously made a 3D-printed model that took an often flat subject and brought it into three dimensions with all the little details. Trilobites were even better, something that, with a few (enrolled) exceptions, we will never get to hold in our hands, free of the substrate.

Many of these mind-blowing trilobite species (like Dicranurus) sport delicate arrays of spines that don't hold up well to the rigors of 3D printing. Many, too, are a bit too simple and rounded to benefit much from 3D printing over simple sculpting.

So I looked at as many ceraurids as I could find, and made 2D drawings, first in pencil, then in Inkscape, to provide guides for the 3D modeling. The initial goal was not to model a specific species, but to capture the organism in a recognizable way. The eyes are larger and more stalked in the drawings, and present model, than in Ceraurus, among a huge number of features that are just wrong. At the same time, any knowledgeable person can identify the genus immediately. Over time, I've been pushing the model closer and closer to identifiable species, influenced in large part by the folks on FF who can identify species instantly from details of an isolated hypostome. No pressure!

A few features in the drawings are worth noting. This trilobite has features that are rightly prized by collectors. It is "inflated," which is to say it has not been flattened. It is complete -- what a luxury! And it has curved its body in a way that suggests it can roll up, a well-known putatively defensive posture for a wide range of trilobites. These features, I hope, make three dimensions a bit more interesting than a bas-relief flattened rendering.

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dadrummond 18

With 2D drawings in hand, I imported them into Blender and began modeling in 3D. Laborious, detail-oriented work over many, many hours, with several points where I wondered why I was doing this, and wouldn't it be more fun to read a book or watch Youtube. The kind of work that the experts micro-sandblasting and air-scribing matrix-embedded bugs into the light will shake their heads at and say, "That's easy!"

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dadrummond 18

The story so far: we have a species group, drawings, and a 3D model. How do we print it in three dimensions?

I normally send digital files to Shapeways, who will professionally print and ship designs in a stupendous array of materials (nylon, acrylic, ceramic, steel, bronze, gold, platinum) for what seems to me a reasonable price.

But I happen to be in an academic department that, thanks to a forward-looking chair, has its own 3D printer, a Formlabs Form 1. So I decided to print my bug myself.

Here's the printer. This is after the print completed, so you can see the trilobite shell up toward the top, to the right. It's upside down, because that's how the Form 1 works.

And here's the raw print, now rightside up. The trilobite shell is in the top left. The legs, gills, and antennae -- spoiler alert! -- are in the bottom right. More about those later.

Next up: freeing the raw 3D print from its supports. I'm dicing this stuff up due to size limitations per post. Bear with me.

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dadrummond 18

So far, we've built a 3D model from 2D drawings inspired/constrained by actual specimens, generated a raw print, and now are ready to tear that 3D print away from its supports. This is vaguely analogous to taking a product out of really annoying packaging.

The fact of life is that the Form 1 printer works by curing tiny dots of liquid plastic resin into solid form with a laser. That means the whole printing process takes place "underwater," in a bath of liquid resin. The curing happens only at a very thin layer at the bottom of the bath, a layer which keeps reforming as the nascent print is continually pulled up and away from the bottom to make room for the next print layer. If you think about it enough, all this requires that every part in a model being printed be attached to the base of the print, to prevent that part from floating away in the resin bath (oversimplifying a bit, here, but this is one of the main problems). Thus, there's a ton of 3D-printed structure attached to your model before it can be printed. That structure, called support material, has to be removed before your piece is free.

I started here, with a trilobite shell still glistening with resin. I washed it for a few minutes in isopropanol, then let it dry overnight.

Then I've got a lovely shell anchored to a mass of support material, like an airship tethered by countless strong cables.

After a bunch of vicious cutting through tough plastic supports with a flush wire cutter, the shell starts to come free.

And finally, the shell is free, leaving scars from its attachment to the supports.

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dadrummond 18

Ok, now we've got a 3D-printed trilobite shell. One that you can hold in your hand, at the upper end of life size for a creature that grew and molted much like modern-day arthropods. And I've got to say that this moment -- which happened a couple of weeks ago -- was pretty thrilling.

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ZiggieCie 147

THX for the essay and photos, they are great. I mentioned on the Forum several months ago about upcomming 3D printing and how valuable it will be in the fossil world. I am very glad you showed up to verify the growth of 3D printing.

We have several members getting into 3D photogrammetry and they are doing some great work on this. I am wondering if these 3D photos can be used for print out?

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dadrummond 18

Ziggie -- yes, you're right, 3D printing is making a huge difference. Thanks for the question. I've opened a new topic to discuss 3D printing of fossil data, so that folks can find trilobite-3D-print related information here and discuss 3D printing fossils more generally there. Hope this makes sense. That post also tries to directly answer your question.

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Deruos 2

I tried as you to print 3D trilobites. I used 3D models found on the web. The first testing with a 3D printer using plastic wire (two first pictures) were very disappointing. Every layer is visible. Another testing with a professional printer using chemical resin was much better (last picture). I want to use these resin models for bronze casting.